Fiber optic connector and method of assembling the same

ABSTRACT

The present invention discloses a fiber optic connector comprises: a ferrule assembly; a spring seat provided behind the ferrule assembly; and a spring provided between the ferrule assembly and the spring seat. The spring seat has a receiving chamber having an insertion port through which a portion of the ferrule assembly is inserted into the receiving chamber; wherein the ferrule assembly is pre-assembled into the receiving chamber of the spring seat in a way that the ferrule assembly is held to be movably engaged with the spring seat. The spring is fitted and compressed in the receiving chamber. As a result, the ferrule assembly, the spring seat and the spring are pre-assembled into an integral assembly before being inserting into a connector housing. All components of the connector except for the housing may be smoothly pulled through a small long pipe as a whole. After being pulled through the pipe, all components of the connector except for the housing may be easily and quickly inserted into the housing as a whole at one time.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National stage for PCT/IB2015/050901, filed 6 Feb.2015, which claims the benefit of Chinese Patent Application No.201410051670.6 filed on Feb. 14, 2014 in the State Intellectual PropertyOffice of China and which applications are incorporated herein byreference. To the extent appropriate, a claim of priority is made toeach of the above disclosed applications.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a fiber optic connector and a method ofassembling the fiber optic connector.

Description of the Related Art

In prior art, optical cables/fibers generally are optically coupled byfollowing ways of:

1) Splicing Optical Fibers in Field

The way of splicing the optical cables/fibers generally comprises stepsof: Firstly, processing ends of the optical fibers (including peelingoff the optical cable, cleaning and cutting the optical fiber of theoptical cable); Secondly, manually or automatically setting optimumsplicing parameters of a splicing machine and relative positions of theoptical fibers to be spliced based on material and type of the opticalfiber; Thirdly, discharging an electric arc with the splicing machine tofuse the ends of the optical fibers, and slowly and linearly pushing theoptical fibers toward each other to optically couple the optical fibers;Finally, contracting a heat shrinkable tube on a coupled joint of theoptical fibers to protect the coupled joint, and winding the opticalfibers to finish all splicing operations in the field. In this case, thesplicing properties (including optical attenuation, echo, and long termreliability, etc.) of the optical fibers are in different degreesdepended on various factors, such as, operation level of a splicingoperator, operation steps, fiber winding level, cleanliness ofelectrodes of the splicing machine, splicing parameters, cleanliness ofworking environment, and so on. In addition, it is necessary to usevarious expensive apparatus, for example, high precision cutting tool,splicing machine or the like, to perform the splicing of the opticalfibers in the field.

2) Cold Coupling Optical Fibers

In this solution, two processed optical fibers are fixed in a highprecision V-shaped or U-shaped groove and aligned to each other. Inaddition, an optical matching paste is filled in the V-shaped orU-shaped groove to fill a gap between end surfaces of the two opticalfibers. Compared with splicing, the cold coupling is relatively simplerand quicker, because the cold coupling does not need an electric powersupply and a heat shrinkable tube to protect the spliced joint. However,the cold coupling is largely depended on cutting quality of the endsurfaces of the optical fibers and the optical matching paste. If thecutting quality is poor, it decreases the coupling properties (includingoptical attenuation, echo, and long term reliability, etc.).Furthermore, as for the cold coupling with the V-shaped or U-shapedgroove, the coupling loss is increased with the variation of thetemperature. With the passage of time, because of the opened V-shaped orU-shaped groove, flowing away, pollution and aging occurring in theoptical matching paste may cause the insertion loss to become larger oreven reduce the optical signal to zero. Thereby, the cold coupling has apoor stability and long-term reliability.

3) Assembling Connector in Field

In the way of assembling connector in field, an optical fiber ispre-embedded in a ferrule. At one end of ferrule, an end surface of astandard connector is pre-polished, and at the other end of the ferrule,the pre-embedded fiber is placed in a high precision V-shaped groovewith an optical matching paste filled therein. During assembling theconnector in the field, the incoming optical fiber/cable is processed inthe field (for example, opening the cable, peeling the fiber, cleaningand cutting the fiber), and inserted into the rear end of the connectoruntil the end surface of incoming fiber abuts against the end surface ofthe pre-embedded fiber in the V-shaped or U-shaped groove, then thefibers are fixed by an external mechanical element. The way ofassembling connector in field has a relatively high cost. In addition,it is necessary to use a special tool and an operation guide provided bythe connector manufacturer. Also, because the optical matching paste isused, it has a poor stability and long-term reliability.

4) Integral Cable/Fiber Assembly in Factory

The integral cable/fiber assembly is manufactured in the factory. As forthis way, it is reliable and is easy to use. However, it cannot beapplied in a limited space, for example, in an application of fiber tothe home or to the resident, it often needs to pull the cable/fiberassembly through a narrow pipe, especially a pipe in which other cablesare paved.

In the above ways in the prior art, there are high requirements on thetool and the operator to assemble the connector in the field.Furthermore, in the prior art, before assembling a ferrule assembly, aspring and a spring seat into the connector housing, the ferruleassembly, the spring and the spring seat are separated from each otherand cannot be pre-assembled together. Thereby, in the prior art, theferrule assembly, the spring and the spring seat must be assembled intothe connector housing one by one. Such way of assembling the connectoris only adapted to assemble the ferrule assembly, the spring and thespring seat into the connector housing in the factory, and is notadapted to assemble the ferrule assembly, the spring and the spring seatinto the connector housing in the field. As a result, the completelyassembled connector in the factory cannot be pulled through the narrowpipe in the field, because the completely assembled connector has alarge profile size.

SUMMARY OF THE INVENTION

The present invention has been made to overcome or alleviate at leastone aspect of the above mentioned disadvantages.

According to an object of the present invention, there is provided afiber optic connector and a method of assembling the fiber opticconnector, wherein a ferrule assembly, a spring and a spring seat areadapted to be pre-assembled to an integral cable assembly having aprofile size less than that of a connector housing. In this way, thecable assembly with less profile size may be easily pulled through anelongated pipe in the field. Furthermore, after pulled through theelongated pipe, the cable assembly as a whole may be quickly assembledinto the connector housing in the field.

According to another object of the present invention, there is provideda fiber optic connector and a method of assembling the fiber opticconnector, wherein all components of the connector except for a housingmay be correctly and quickly assembled into the connector housing,effectively saving the assembling time and reducing mistake operations.

According to another object of the present invention, there is provideda fiber optic connector and a method of assembling the fiber opticconnector, wherein all components of the connector except for a housingcan be pre-assembled to an integral assembly, and an end surface of aferrule and a fiber are protected from damage during assembling theintegral assembly into the connector housing, improving the long termreliability of an interconnection of fiber optic connectors.

According to an aspect of the present invention, there is provided afiber optic connector comprising: a ferrule assembly; a spring seatprovided behind the ferrule assembly; and a spring provided between theferrule assembly and the spring seat, wherein the spring seat has areceiving chamber having an insertion port through which a portion ofthe ferrule assembly is inserted into the receiving chamber; wherein theferrule assembly is pre-assembled into the receiving chamber of thespring seat in a way that the ferrule assembly is held to be movablyengaged with the spring seat, and the spring is fitted and compressed inthe receiving chamber, so that the ferrule assembly, the spring seat andthe spring are pre-assembled into an integral assembly before beinginserting into a connector housing.

According to an exemplary embodiment of the present invention, thespring is pre-assembled in the receiving chamber together with theferrule assembly or before pre-assembling the ferrule assembly.

According to another exemplary embodiment of the present invention, theferrule assembly comprises: a ferrule; and a ferrule seat with a frontend fixedly connected to the ferrule and a rear end assembled into thereceiving chamber of the spring seat.

According to another exemplary embodiment of the present invention, theferrule and the ferrule seat are formed into a single piece.

According to another exemplary embodiment of the present invention, aprotrusion is formed on an outer circumference of the ferrule seat; abackstop portion is formed in the receiving chamber of the spring seat;and the backstop portion is configured to abut against the protrusionafter the rear end of the ferrule seat is assembled into the receivingchamber of the spring seat, so as to prevent the ferrule seat from beingwithdrawn from the spring seat.

According to another exemplary embodiment of the present invention, theprotrusion is configured to continuously surround a full circle of theouter circumference of the ferrule seat.

According to another exemplary embodiment of the present invention, thebackstop portion is configured to be a stopping flange, extendinginwardly, formed at an edge of the insertion port of the receivingchamber.

According to another exemplary embodiment of the present invention, thebackstop portion is configured to be an elastic snapper formed in thereceiving chamber.

According to another exemplary embodiment of the present invention, anopening is formed in the sidewall of the receiving chamber of the springseat, and the spring is pre-assembled in the receiving chamber throughthe opening.

According to another exemplary embodiment of the present invention, theprotrusion comprises a plurality of local protrusions, separated fromeach other, on the outer circumference of the ferrule seat.

According to another exemplary embodiment of the present invention, aplurality of slots are formed in the sidewall of the receiving chamberof the spring seat, and the backstop portion is directly composed offront edges of the slots.

According to another exemplary embodiment of the present invention, thespring is pre-assembled into the receiving chamber through the insertionport of the spring seat.

According to another exemplary embodiment of the present invention, thefiber optic connector further comprises: a dust cap fitted on a frontend of the ferrule; a crimp ring configured to crimp a strengtheningelement of an optical cable on a rear end of the spring seat; and astress relief tube sleeved on the crimp ring crimped on the rear end ofthe spring seat.

According to another exemplary embodiment of the present invention, theoptical cable, the dust cap, the ferrule assembly, the spring seat, thespring, the crimp ring and the stress relief tube are pre-assembledtogether to form a first cable connection assembly as a whole beforeinserting into the connector housing.

According to another exemplary embodiment of the present invention, theconnector housing comprises: an outer housing; and an inner housingadapted to be fitted in the outer housing.

According to another exemplary embodiment of the present invention, thefirst cable connection assembly is inserted into the connector housinguntil a protruding portion formed on the spring seat is snap-fitted in arecess formed in the inner housing, so as to assemble the first cableconnection assembly and the connector housing together; and the dust capfitted on the front end of the ferrule extends out through a hole formedin a front portion of the connector housing during inserting the firstcable connection assembly into the connector housing, so as to protect afront end surface of the ferrule from damage.

According to another exemplary embodiment of the present invention, afirst positioning key is formed on an inner wall of the inner housing,and a positioning slot, matched with the first positioning key, isformed in the ferrule seat, to ensure that the first cable connectionassembly is correctly inserted into the connector housing.

According to another exemplary embodiment of the present invention, thefirst cable connection assembly is pre-assembled into the inner housingto form a second cable connection assembly, and the second cableconnection assembly as a whole is inserted into the outer housing toform a complete fiber optic connector.

According to another aspect of the present invention, there is provideda method of assembling a fiber optic connector, comprising steps of:

-   -   S10: pre-assembling all components of the fiber optic connector,        except for a connector housing, together to form a first cable        connection assembly as a whole; and    -   S20: inserting the first cable connection assembly as a whole        into the connector housing to form a complete fiber optic        connector,    -   wherein the fiber optic connector comprises a ferrule assembly,        a spring seat, a spring, and the connector housing, and    -   wherein the ferrule assembly is pre-assembled into a receiving        chamber of the spring seat in a way that the ferrule assembly        may be moved relative to the spring seat and cannot be separated        from the spring seat, so as to compress the spring in the        receiving chamber.

According to an exemplary embodiment of the present invention, the abovemethod further comprises a step of: pulling the first cable connectionassembly through an elongated pipe before the step S20.

According to another aspect of the present invention, there is provideda method of assembling a fiber optic connector having an inner housingand an outer housing, the method comprising steps of:

-   -   S100: pre-assembling all components of the fiber optic        connector, except for the outer housing, together to form a        second cable connection assembly as a whole; and    -   S200: inserting the second cable connection assembly as a whole        into the outer housing to form a complete fiber optic connector,    -   wherein the fiber optic connector further comprises a ferrule        assembly, a spring seat and a spring, and    -   wherein the ferrule assembly is pre-assembled into a receiving        chamber of the spring seat in a way that the ferrule assembly is        held to be movably engaged with the spring seat, so as to        compress the spring in the receiving chamber.

According to an exemplary embodiment of the present invention, the abovemethod further comprises a step of: pulling the second cable connectionassembly through an elongated pipe before the step S200.

In the fiber optic connector and the method of assembling the fiberoptic connector according to the above exemplary embodiments of thepresent invention, before being inserted into a housing of theconnector, the ferrule assembly, the spring seat and the spring may bepre-assembled together to form an integral assembly having a size lessthan that of a housing of the connector. Accordingly, all components ofthe connector except for the housing may be smoothly pulled through asmall long pipe as a whole. Furthermore, after being pulled through thepipe, all components of the connector except for the housing may beeasily and quickly inserted into the housing as a whole at one time,saving the assembly time, avoiding mistake operations, effectivelypreventing the warp of the spring, protecting the end surface of theferrule and the fiber from being damaged during the assembling process,increasing the long term reliability of the interconnection of the fiberoptic connectors.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will become moreapparent by describing in detail exemplary embodiments thereof withreference to the accompanying drawings, in which:

FIG. 1 is an illustrative perspective view of a first cable connectionassembly formed by assembling all components of a fiber optic connectorexcept for a housing according to an exemplary embodiment of the presentinvention;

FIG. 2 is an illustrative view of a ferrule assembly of FIG. 1;

FIG. 3 is an illustrative view of a ferrule assembly, a spring and aspring seat pre-assembled together;

FIG. 4 is an illustrative cross section view of the ferrule assembly,the spring and the spring seat pre-assembled together shown in FIG. 3;

FIG. 5 is an illustrative view of the spring seat and the spring shownin FIG. 3 before the spring is mounted in the spring seat;

FIG. 6 is an illustrative view of the spring seat and the spring shownin FIG. 3 after the spring is mounted in the spring seat;

FIG. 7 is an illustrative cross section view of the first cableconnection assembly shown in FIG. 1;

FIG. 8 is an illustrative view of a ferrule assembly according toanother exemplary embodiment of the present invention;

FIG. 9 is an illustrative view of a ferrule assembly, a spring and aspring seat pre-assembled together according to another exemplaryembodiment of the present invention;

FIG. 10 is an illustrative cross section view of the ferrule assembly,the spring and the spring seat pre-assembled together shown in FIG. 9;

FIG. 11 is an illustrative perspective view of a connector housingaccording to an exemplary embodiment of the present invention;

FIG. 12 is an illustrative cross section view of the connector housingof FIG. 11;

FIG. 13 is an illustrative perspective view of a fiber optic connectorformed by assembling the first cable connection assembly of FIG. 1 intothe connector housing of FIG. 12;

FIG. 14 is an illustrative cross section view of the fiber opticconnector of FIG. 13;

FIG. 15 is an illustrative exploded view of a connector housingaccording to an exemplary embodiment of the present invention;

FIG. 16 is an illustrative perspective view of a second cable connectionassembly formed by assembling the first cable connection assembly ofFIG. 1 into an inner housing of the connector housing of FIG. 15; and

FIG. 17 is an illustrative perspective view of a fiber optic connectorformed by assembling the second cable connection assembly of FIG. 16into an outer housing of the connector housing of FIG. 15.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Exemplary embodiments of the present disclosure will be describedhereinafter in detail with reference to the attached drawings, whereinthe like reference numerals refer to the like elements. The presentdisclosure may, however, be embodied in many different forms and shouldnot be construed as being limited to the embodiment set forth herein;rather, these embodiments are provided so that the present disclosurewill be thorough and complete, and will fully convey the concept of thedisclosure to those skilled in the art.

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details. In other instances, well-known structures and devicesare schematically shown in order to simplify the drawing.

According to a general concept of the present invention, there isprovided a fiber optic connector comprising: a ferrule assembly; aspring seat provided behind the ferrule assembly; and a spring providedbetween the ferrule assembly and the spring seat, wherein the springseat has a receiving chamber having an insertion port through which aportion of the ferrule assembly is inserted into the receiving chamber;wherein the ferrule assembly is pre-assembled into the receiving chamberof the spring seat in a way that the ferrule assembly is held to bemovably engaged with the spring seat, that is, the ferrule assembly maybe moved relative to the spring seat and cannot be separated from thespring seat, and the spring is fitted and compressed in the receivingchamber, so that the ferrule assembly, the spring seat and the springare pre-assembled into an integral assembly before being inserting intoa connector housing.

FIG. 1 is an illustrative perspective view of a first cable connectionassembly 1 formed by assembling all components of a fiber opticconnector except for a housing according to an exemplary embodiment ofthe present invention; FIG. 7 is an illustrative cross section view ofthe first cable connection assembly 1 shown in FIG. 1.

In an exemplary embodiment of the present invention, as shown in FIGS. 1and 7, the fiber optic connector mainly comprises a connector housing(see FIG. 11, however, not shown in FIG. 1), a ferrule 100, a ferruleseat 200, a spring seat 300, a spring 400, a dust cap 500, a stressrelief tube 600, a crimp ring 700 and an optical cable 10.

As shown in FIGS. 1 and 7, the dust cap 500 is fitted on a front end(distal end) of the ferrule 100, so as to protect a front end surface ofthe ferrule 100 and a fiber of the optical cable 10. A rear end(proximal end) of the ferrule 100 is fixed to the ferrule seat 200. Thespring 400 is mounted in the spring seat 300. A rear end of the ferruleseat 200 is assembled into the spring seat 300 and compresses the spring400 in the spring seat 300. A strengthening element (not shown, forexample, Kevlar elements) of the optical cable 10 is crimped on a rearend 302 (FIG. 3) of the spring seat 300 by the crimp ring 700. Thestress relief tube 600 is sleeved on the crimp ring 700. In this way,the first cable connection assembly 1 as shown in FIG. 1 is obtained.

FIG. 2 is an illustrative view of a ferrule assembly of FIG. 1; FIG. 3is an illustrative view of a ferrule assembly, a spring 400 and a springseat 300 pre-assembled together; and FIG. 4 is an illustrative crosssection view of the ferrule assembly, the spring 400 and the spring seat300 pre-assembled together shown in FIG. 3.

Hereafter, it will describe in detail the structures of the ferrule seat200, the spring 400 and the spring seat 300 with reference to FIGS. 2-4.

As shown in FIG. 4, the spring seat 300 has a receiving chamber 306having an insertion port facing the ferrule seat 200. The rear end ofthe ferrule seat 200 is adapted to be inserted into the receivingchamber 306 through the insertion port.

As shown in FIGS. 2-4, the ferrule seat 200 comprises keys 204 adjacentto the ferrule 100, a first cylindrical portion 201 provided at rearside of the keys 204, a second cylindrical portion 202 connected to thefirst cylindrical portion 201, and a protrusion 203 formed on the firstcylindrical portion 201 opposite to the keys 204.

As shown in FIGS. 2-4, the receiving chamber 306 is formed in the frontportion 301 of the spring seat 300, and a backstop portion 303 is formedin the receiving chamber 306 of the spring seat 300. In this way, whenthe rear end of the ferrule seat 200 is inserted into the receivingchamber 306 of the spring seat 300, the backstop portion 303 abutsagainst the protrusion 203, so as to prevent the ferrule seat 200 frombeing disengaged from the spring seat 300.

As shown in FIGS. 2-4, the second cylindrical portion 202 of the ferruleseat 200 has an outer diameter less than that of the first cylindricalportion 201 and less than an inner diameter of the spring 400. In thisway, the second cylindrical portion 202 is capable of being insertedinto the receiving chamber of the spring seat 300 and passing throughthe spring 400.

As shown in FIGS. 2-4, the protrusion 203 of the ferrule seat 200 has anouter diameter slightly larger than an inner diameter of the insertionport of the spring seat 300. Thereby, during inserting the rear end ofthe ferrule seat 200 into the receiving chamber 306 of the spring seat300, the insertion port of the spring seat 300 is expanded outward underthe action of the protrusion 203, to allow the protrusion 203 to enterinto the receiving chamber 306. Once the protrusion 203 enters into thereceiving chamber 306, the protrusion 203 compresses the spring 300 inthe receiving chamber 306 and abuts against the backstop portion 303,which has been returned to its original position, under the action ofthe spring 300. In this way, the ferrule seat 200 cannot be withdrawnfrom the receiving chamber 306.

As shown in FIGS. 2-4, the first cylindrical portion 201 of the ferruleseat 200 has an outer diameter less than an inner diameter of thereceiving chamber 306. Thereby, the ferrule seat 200 can be movedforward and backward in the receiving chamber 306 of the spring seat 300by a predetermined distance, but cannot be disengaged from the receivingchamber 306 of the spring seat 300 due to engagement of the backstopportion 303 and the protrusion 203. In this way, the ferrule assembly,the spring seat 300 and the spring 400 are pre-assembled into anintegral assembly before being inserting into the connector housing.

FIG. 5 is an illustrative view of the spring seat 300 and the spring 400shown in FIG. 3 before the spring is mounted in the spring seat 300; andFIG. 6 is an illustrative view of the spring seat 300 and the spring 400shown in FIG. 3 after the spring 400 is mounted in the spring seat 300.

As shown in FIGS. 5 and 6, an opening 305 is formed in the sidewall ofthe receiving chamber 306 of the spring seat 300. By compressing thespring 400 to reduce the length of the spring 400, the spring 400 can bemounted in the receiving chamber 306 through the opening 305.

In an exemplary embodiment, as shown in FIGS. 2-4, the protrusion 203 isconfigured to continuously surround a full circle of the outercircumference of the ferrule seat 200. The backstop portion 303 isconfigured to be a stopping flange, extending inwardly, formed at anedge of the insertion port of the receiving chamber 306.

FIG. 8 is an illustrative view of a ferrule assembly according toanother exemplary embodiment of the present invention; FIG. 9 is anillustrative view of a ferrule assembly, a spring and a spring seatpre-assembled together according to another exemplary embodiment of thepresent invention; and FIG. 10 is an illustrative cross section view ofthe ferrule assembly, the spring and the spring seat pre-assembledtogether shown in FIG. 9.

As shown in FIGS. 8-10, a plurality of local protrusions 203′, separatedfrom each other at a predetermined interval, are formed on the outercircumference of the ferrule seat 200′. A plurality of slots 305′ areformed in the sidewall of the receiving chamber of the spring seat 300′,and the backstop portion 303′ is directly composed of front edges of theslots 305′. When the rear end of the ferrule seat 200′ is inserted intothe receiving chamber of the spring seat 300′, the plurality of localprotrusions 203′ are received in the plurality of slots 305′ and abutagainst the front edges of the slots 305′ under the action of the spring400. In this way, it can prevent the ferrule seat 200′ from beingwithdrawn from the receiving chamber of the spring seat 300′.

Although it has shown two different configurations for assembling theferrule seat 200 and the spring seat 300 together, but the presentinvention is not limited to the illustrated embodiments, for example,the backstop portion 303 may be an elastic snapper formed in thereceiving chamber 306 as long as it can prevent the ferrule seat 200from being withdrawn from the spring seat 300.

FIG. 11 is an illustrative perspective view of a connector housingaccording to an exemplary embodiment of the present invention; FIG. 12is an illustrative cross section view of the connector housing of FIG.11; FIG. 13 is an illustrative perspective view of a fiber opticconnector formed by assembling the first cable connection assembly ofFIG. 1 into the connector housing of FIG. 12; and FIG. 14 is anillustrative cross section view of the fiber optic connector of FIG. 13.

As shown in FIGS. 11-14, in an exemplary embodiment, before beinginserting into the connector housing, the optical cable 10, the dust cap500, the ferrule assembly, the spring seat 300, the spring 400, thecrimp ring 700 and the stress relief tube 600 are pre-assembled togetherto form the integral first cable connection assembly 1 as shown inFIG. 1. Then, the first cable connection assembly 1 as a whole isinserted into the connector housing until a protruding portion 304formed on the spring seat 300 is snap-fitted in a recess formed in aninner housing 900 of the connector housing. In this way, the first cableconnection assembly 1 and the connector housing are assembled togetherto form a complete fiber optic connector. During inserting the firstcable connection assembly 1 into the connector housing, the dust cap 500is not taken off from the first cable connection assembly 1, and thedust cap 500 fitted on the front end of the ferrule 100 extends outthrough a hole formed in a front portion of the connector housing. Inthis way, it can effectively protect the front end surface of theferrule 100 from damage.

As shown in FIG. 12, a first positioning key 901 is formed on an innerwall of the inner housing 900, and a positioning slot (not shown),matched with the first positioning key 901, is formed in the ferruleseat 200. Only when the positioning slot in the ferrule seat 200 isaligned to the first positioning key 901 on the inner housing 900, thefirst cable connection assembly 1 may be inserted into the connectorhousing. Thereby, it can ensure that the first cable connection assembly1 is correctly inserted into the connector housing.

As shown in FIG. 12, the first positioning key 901 on the inner housing900 is configured to align with a second positioning key 801 formed onthe outer housing 800, and the second positioning key 801 on the outerhousing 800 is configured to be fitted in a positioning slot formed inan adapter (not shown) for receiving the fiber optic connector.

In the illustrated embodiment, because the dust cap 500 is pre-assembledon the front end of the ferrule 100 before the first cable connectionassembly 1 is inserted into the connector housing, it can effectivelyprotect the front end surface of the ferrule 100 and the optical fiberfrom damage during assembling the first cable connection assembly 1 intothe connector housing.

FIG. 15 is an illustrative exploded view of a connector housingaccording to an exemplary embodiment of the present invention; FIG. 16is an illustrative perspective view of a second cable connectionassembly 2 formed by assembling the first cable connection assembly 1 ofFIG. 1 into an inner housing 900 of the connector housing of FIG. 15;and FIG. 17 is an illustrative perspective view of a fiber opticconnector formed by assembling the second cable connection assembly 2 ofFIG. 16 into an outer housing 800 of the connector housing of FIG. 15.

As shown in FIGS. 15-17, the connector housing comprises an outerhousing 800 and an inner housing 900 adapted to be fitted in the outerhousing 800.

In an exemplary embodiment, as shown in FIGS. 15-17, the first cableconnection assembly 1 is pre-assembled into the inner housing 900 toform a second cable connection assembly 2. Thereafter, the second cableconnection assembly 2 as a whole is inserted into the outer housing 800to form a complete fiber optic connector.

According to another exemplary embodiment, there is also disclosed amethod of assembling a fiber optic connector, comprising steps of:

-   -   S10: pre-assembling all components of the fiber optic connector,        except for a connector housing, together to form a first cable        connection assembly 1 as a whole; and    -   S20: inserting the first cable connection assembly 1 as a whole        into the connector housing to form a complete fiber optic        connector.

The fiber optic connector comprises a ferrule assembly, a spring seat300, a spring 400 and the connector housing. The ferrule assembly ispre-assembled into a receiving chamber 306 of the spring seat 300 in away that the ferrule assembly is held to be movably engaged with thespring seat, that is, the ferrule assembly may be moved relative to thespring seat 300 and cannot be separated or withdrawn from the springseat 300, so as to compress the spring 400 in the receiving chamber 306.

In an exemplary embodiment of the present invention, the above methodfurther comprises a step of: pulling the first cable connection assembly1 through an elongated pipe before the step S20.

According to another exemplary embodiment, there is also disclosed amethod of assembling a fiber optic connector having an inner housing 900and an outer housing 800, the method comprising steps of:

-   -   S100: pre-assembling all components of the fiber optic        connector, except for the outer housing 800, together to form a        second cable connection assembly 2 as a whole; and    -   S200: inserting the second cable connection assembly 2 as a        whole into the outer housing 800 to form a complete fiber optic        connector.

The fiber optic connector further comprises a ferrule assembly, a springseat 300 and a spring 400. The ferrule assembly is pre-assembled into areceiving chamber 306 of the spring seat 300 in a way that the ferruleassembly is held to be movably engaged with the spring seat, that is,the ferrule assembly may be moved relative to the spring seat 300 andcannot be separated or withdrawn from the spring seat 300, so as tocompress the spring 400 in the receiving chamber 306.

In an exemplary embodiment of the present invention, the above methodfurther comprises a step of: pulling the second cable connectionassembly 2 through an elongated pipe before the step S200.

In the fiber optic connector and the method of assembling the fiberoptic connector according to the above exemplary embodiments of thepresent invention, the ferrule assembly, the spring seat and the springmay be pre-assembled together to form an integral assembly having a sizeless than that of the connector housing. Accordingly, all components ofthe connector except for the connector housing may be smoothly pulledthrough a long narrow pipe as a whole. Furthermore, after being pulledthrough the pipe, all components of the connector except for theconnector housing may be easily and quickly inserted into the connectorhousing as a whole at one time, saving the assembly time, avoidingmistake operations, effectively preventing the warp of the spring,protecting the end surface of the ferrule and the fiber from beingdamaged during the assembling process, increasing the long termreliability of interconnection of the fiber optic connectors.

It should be appreciated for those skilled in this art that the aboveembodiments are intended to be illustrated, and not restrictive. Forexample, many modifications may be made to the above embodiments bythose skilled in this art, and various features described in differentembodiments may be freely combined with each other without conflictingin configuration or principle.

Although several exemplary embodiments have been shown and described, itwould be appreciated by those skilled in the art that various changes ormodifications may be made in these embodiments without departing fromthe principles and spirit of the disclosure, the scope of which isdefined in the claims and their equivalents.

As used herein, an element recited in the singular and proceeded withthe word “a” or “an” should be understood as not excluding plural ofsaid elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising” or “having”an element or a plurality of elements having a particular property mayinclude additional such elements not having that property.

What is claimed is:
 1. A fiber optic connector comprising: a ferruleassembly including a ferrule and a ferrule seat, a front end of theferrule seat being fixedly connected to the ferrule; a spring seatprovided at least partially behind the ferrule assembly, a rear end ofthe ferrule seat being assembled into a receiving chamber of the springseat; and a spring provided between the ferrule assembly and a portionof the spring seat, wherein the receiving chamber has an insertion portthrough which a portion of the ferrule assembly is inserted into thereceiving chamber; wherein the ferrule assembly is pre-assembled intothe receiving chamber of the spring seat in a way that the ferruleassembly is held to be movably engaged with the spring seat, and thespring is fitted and compressed in the receiving chamber, so that theferrule assembly, the spring seat and the spring are pre-assembled intoan integral assembly before being inserted into a connector housing;wherein a protrusion is formed on an outer circumference of the ferruleseat, the protrusion being configured to continuously surround a fullcircle of the outer circumference of the ferrule seat; wherein abackstop portion is formed in the receiving chamber of the spring seat;wherein the backstop portion is configured to abut against theprotrusion after the rear end of the ferrule seat is assembled into thereceiving chamber of the spring seat, so as to prevent the ferrule seatfrom being disengaged from the spring seat; and wherein the backstopportion is configured to be a stopping flange, extending inwardly,formed at an edge of the insertion port of the receiving chamber.
 2. Thefiber optic connector according to claim 1, wherein the spring ispre-assembled in the receiving chamber together with the ferruleassembly or before pre-assembling the ferrule assembly.
 3. The fiberoptic connector according to claim 1, wherein the ferrule and theferrule seat are formed into a single piece.
 4. The fiber opticconnector according to claim 1, wherein the backstop portion comprisesan elastic snapper.
 5. The fiber optic connector according to claim 1,wherein an opening is formed in a sidewall of the receiving chamber ofthe spring seat, and wherein the spring is pre-assembled in thereceiving chamber through the opening.
 6. The fiber optic connectoraccording to claim 1, wherein the spring is pre-assembled into thereceiving chamber through the insertion port of the spring seat.
 7. Thefiber optic connector according to claim 1, further comprising: a dustcap fitted on a front end of the ferrule; a crimp ring configured tocrimp a strengthening element of an optical cable on a rear end of thespring seat; and a stress relief tube sleeved on the crimp ring crimpedon the rear end of the spring seat.
 8. The fiber optic connectoraccording to claim 7, wherein the optical cable, the dust cap, theferrule assembly, the spring seat, the spring, the crimp ring and thestress relief tube are pre-assembled together to form a first cableconnection assembly before the first cable connection assembly isinserted into the connector housing.
 9. The fiber optic connectoraccording to claim 8, wherein the connector housing comprises: an outerhousing; and an inner housing adapted to be fitted in the outer housing.10. The fiber optic connector according to claim 9, wherein the firstcable connection assembly is inserted into the connector housing until aprotruding portion formed on the spring seat is snap-fitted in a recessformed in the inner housing, so as to assemble the first cableconnection assembly and the connector housing together; and wherein thedust cap fitted on the front end of the ferrule extends out through ahole formed in a front portion of the connector housing during insertingthe first cable connection assembly into the connector housing, so as toprotect a front end surface of the ferrule from damage.
 11. The fiberoptic connector according to claim 10, wherein a first positioning keyis formed on an inner wall of the inner housing, and wherein apositioning slot, matched with the first positioning key, is formed inthe ferrule seat, to ensure that the first cable connection assembly iscorrectly inserted into the connector housing.
 12. The fiber opticconnector according to claim 9, wherein the first cable connectionassembly is pre-assembled into the inner housing to form a second cableconnection assembly, and wherein the second cable connection assembly isinserted into the outer housing to form a complete fiber opticconnector.
 13. A method of assembling a fiber optic connector,comprising steps of: pre-assembling all components of the fiber opticconnector, except for a connector housing, together to form a firstcable connection assembly; and inserting the first cable connectionassembly into the connector housing to form a complete fiber opticconnector, wherein the fiber optic connector comprises a ferruleassembly, a spring seat, a spring, and the connector housing, whereinthe spring seat has a receiving chamber having an insertion port and thepre-assembling includes inserting a portion of the ferrule assemblythrough the insertion port into the receiving chamber, wherein theferrule assembly is pre-assembled into a receiving chamber of the springseat in a way that a protrusion formed on an outer circumference of aferrule seat of the ferrule assembly and configured to continuouslysurround a full circle of the outer circumference of the ferrule seatabuts against a back stop disposed in the receiving chamber of thespring seat so as to prevent the ferrule seat from being disengaged fromthe spring seat and such that the ferrule assembly is held to be movablyengaged with the spring seat, so as to compress the spring in thereceiving chamber, and wherein the backstop is configured to be astopping flange, extending inwardly, formed at an edge of the insertionport of the receiving chamber.
 14. The method according to claim 13,further comprising a step of: pulling the first cable connectionassembly through an elongated pipe before the inserting step.
 15. Amethod of assembling a fiber optic connector having an inner housing andan outer housing, the method comprising steps of: pre-assembling allcomponents of the fiber optic connector, except for the outer housing,together to form a second cable connection assembly; and inserting thesecond cable connection assembly into the outer housing to form acomplete fiber optic connector, wherein the fiber optic connectorfurther comprises a ferrule assembly, a spring seat and a spring,wherein the spring seat has a receiving chamber having an insertion portand the pre-assembling includes inserting a portion of the ferruleassembly through the insertion port into the receiving chamber, whereinthe ferrule assembly is pre-assembled into a receiving chamber of thespring seat in a way that a protrusion formed on an outer circumferenceof a ferrule seat of the ferrule assembly and configured to continuouslysurround a full circle of the outer circumference of the ferrule seatabuts against a back stop disposed in the receiving chamber of thespring seat and such that the ferrule assembly may be moved relative tothe spring seat and cannot be separated from the spring seat, so as tocompress the spring in the receiving chamber, and wherein the backstopis configured to be a stopping flange, extending inwardly, formed at anedge of the insertion port of the receiving chamber.
 16. The methodaccording to claim 15, further comprising a step of: pulling the secondcable connection assembly through an elongated pipe before the insertingstep.
 17. The method according to claim 13, wherein the pre-assemblingincludes inserting the spring through the insertion port into thereceiving chamber of the spring seat.
 18. The method according to claim15, wherein the pre-assembling includes inserting the spring through theinsertion port into the receiving chamber of the spring seat.
 19. Afiber optic connector comprising: a ferrule assembly; a spring seatprovided at least partially behind the ferrule assembly; and a springprovided between the ferrule assembly and a portion of the spring seat,wherein the spring seat has a receiving chamber having an insertion portat a front end through which a portion of the ferrule assembly isinserted into the receiving chamber, the receiving chamber beingpartially defined by a side wall that extends from the front end to aback end of the receiving chamber and surrounds a longitudinal axis ofthe fiber optic connector; wherein the ferrule assembly is pre-assembledinto the receiving chamber of the spring seat in a way that the ferruleassembly is held to be movably engaged with the spring seat, and thespring is fitted and compressed in the receiving chamber, so that theferrule assembly, the spring seat and the spring are pre-assembled intoan integral assembly before being inserting into a connector housing;wherein an opening is formed in the sidewall of the receiving chamber ofthe spring seat, and wherein the spring is pre-assembled in thereceiving chamber through the opening.